ESE's works engine tuner

[speedpro]

With the ProX rod kits I'd suggest you check the bearings they come with and if they aren't flat silver plated cages order ones that are.

[kel]

With the ProX rod kits I'd suggest you check the bearings they come with and if they aren't flat silver plated cages order ones that are.

I think Husaberg is referencing the TKRK catalogue. ProX is mostly motocross (i.e. competition) focused although I have noticed MB and other odd rods in their catalogue. Speedpro did you have a chance to look up those rod dimensions for me?

[husaberg]

I think Husaberg is referencing the TKRK catalogue. ProX is mostly motocross (i.e. competition) focused although I have noticed MB and other odd rods in their catalogue. Speedpro did you have a chance to look up those rod dimensions for me?

Yeah TKRJ
The ProX rods and bearings are in my opinion legal (As long as don't say they are specifically for a certain competition engine) So as they are not indexed as competition bike Say RM or CR etc i say they are A ok. but that's only my opinion though.
But as speedpro say the bearing will have to be replaced with silver plated solid ones PVL has some beautiful ones as do the Samarin but would be iffey legality.
so it may well be Prox for the bearings.
All the links including the Samarin rod search and the Mad swede, Breedon site, plus capt,Tkrj and others are on the wrist pin thread of Yows though.(Added below)
I think i also have the defunct Ryteching info on file as well somewhere. i started a spread sheet based on the breedon site (attached below).
I was going to try and format all the separate rod and piston stuff onto one Excel sheet when i get some time and enthusiasm.

http://http://www.samarin.net/?productos
http://www.pvlsverige.se/vrm/index/index22.html
http://www.mxcomposites.com/con_rod.php
http://www.connectingrod.com.tw/ktm.htm
http://www.pro-x.com/downloads/Technical.pdf
http://www.kevinbreedonracing.co.uk/...ts_conrods.asp
http://www.connectingrod.com.tw/honda.htm
http://www.samarin.nl/webshop/index....ewCat&catId=32
http://www.tkrj.co.jp/
http://findebookee.com/c/connecting-rod the one is capt

[dmcca]

As we have discussed on other forums the Blow STA is all important

Is this on a public forum(s)?

I would be very interested to read more on your combined thoughts on STA's and blowdown if its accessible to an average joe wannabe tuner like me. Its an area that i sometimes feel hazy over, particularly the relationship between exhaust, blowdown and transfers for different applications, and dont want to ask stupid questions just yet so reading your discussions might help clarify a few things.

[husaberg]

Is this on a public forum(s)?

I would be very interested to read more on your combined thoughts on STA's and blowdown if its accessible to an average joe wannabe tuner like me. Its an area that i sometimes feel hazy over, particularly the relationship between exhaust, blowdown and transfers for different applications, and dont want to ask stupid questions just yet so reading your discussions might help clarify a few things.

TFFT
I thought i was the only one
I mostly feel the same although both concepts are in books going back to Bacon and co they are always mentioned but never really explained,
Robinson and even bell mention it as does Draper but only generally although Robinson did a good job and even included a program (BBC unfortunately) I think he was doing a new edition when he died to calculate it.
Jennings does as well in hindsight with time area based on the Yam SAE papers.
but Blowdown is an area i struggle with at times to really thoroughly get my head around and i not afraid to admit that.

[dmcca]

TFFT
I thought i was the only one
I mostly feel the same although both concepts are in books going back to Bacon and co they are always mentioned but never really explained,
Robinson and even bell mention it as does Draper but only generally although Robinson did a good job and even included a program (BBC unfortunately) I think he was doing a new edition when he died to calculate it.
Jennings does as well in hindsight with time area based on the Yam SAE papers.
but Blowdown is an area i struggle with at times to really thoroughly get my head around and i not afraid to admit that.

[Frits Overmars]

Is this on a public forum(s)? I would be very interested to read more on your combined thoughts on STA's and blowdown if its accessible to an average joe wannabe tuner like me. Its an area that i sometimes feel hazy over, particularly the relationship between exhaust, blowdown and transfers for different applications, and dont want to ask stupid questions just yet so reading your discussions might help clarify a few things.

Some of it is on a public forum: http://www.pit-lane.biz/t117p246-gp1...es-aprilia-rsa . But most of it is not. And I am not even at liberty to reveal the forum's name, let alone publish members' contributions here. But what I can do, is show you some of my own contributions, rather randomly scraped together because A: I cannot spare the time, and B: that forum's search function (like any forum's that I know) is useless. Here goes:
---------------------------------------------------------------------
Time* area:
You start with a port in a cylinder. That port has a certain area.
Put that cylinder on a crankcase containing a crankshaft with a certain stroke and a certain conrod/stroke-ratio.
Turning the crankshaft will give a certain angle*area for the port in the cylinder. So you can say that a port in a cylinder on an engine has a certain angle*area.
Adding rpm will assign a certain time to that angle which gives us a time*area value. So a port in a cylinder on a running engine has a certain time*area.
And finally dividing that TA value by the cylinder capacity, including the combustion volume (which everybody keeps forgetting) will give the specific time*area, which is an indication of how well an engine can breathe and at what rpm it will run out of breath.
By the way, I like to use the multiplication sign * in angle*area and time*area because I feel it clarifies what these expressions stand for.

While we are on the subject of breathing: STA is essential but it is not the only factor. You can have all the STA you want; with a pressure ratio ≤ 1 over a port no mass will start moving in the desired direction.

The third essential factor is inertia. Even with ample STA and a healthy pressure ratio a stationary gas column needs time to get up to speed. The longer and heavier the column, the slower it gets moving.
(when talking about intake ducts you might argue that such a sluggish column will give a useful ramming effect later on, but I would say that this is just an attempt at the end to make up for something that went wrong at the beginning).
Summary: it all comes down to ports and pipes. But you already knew that.
-------------------------------------------------------------------------------
Gordon Jennings certainly did a lot of good with his easy-to-read articles. But he created one misconception that is festering until this day, with his translation of the SAE-papers of Yamaha's Naitoh and Nomura into 'tuner's english'.
He extracted specific time*areas and claimed them to be the optimum values for a two-stroke. On the scavenging side he was as right as makes no difference, but on the exhaust side it was quite another story.
Naitoh and Nomura just stated their findings; Jennings concluded that specific exhaust time*area should be what Yamaha had been using. But Yamaha had by no means found a gasdynamic optimum; they just had gone as far as the quality of their piston rings allowed them to do. And had they thought of using auxiliary exhaust ducts (first seen in their present form in the 1971 Jamathi engine), they would have made a quantum leap.
Another point of criticism is that Jennings emphasized exhaust time*area and almost neglected blowdown time*area.
----------------------------------------------------------------

[husaberg]

Some of it is on a public forum: http://www.pit-lane.biz/t117p246-gp1...es-aprilia-rsa . But most of it is not. And I am not even at liberty to reveal the forum's name, let alone publish members' contributions here. But what I can do, is show you some of my own contributions, rather randomly scraped together because A: I cannot spare the time, and B: that forum's search function (like any forum's that I know) is useless. Here goes:
---------------------------------------------------------------------
Time* area:
You start with a port in a cylinder. That port has a certain area.
Put that cylinder on a crankcase containing a crankshaft with a certain stroke and a certain conrod/stroke-ratio.
Turning the crankshaft will give a certain angle*area for the port in the cylinder. So you can say that a port in a cylinder on an engine has a certain angle*area.
Adding rpm will assign a certain time to that angle which gives us a time*area value. So a port in a cylinder on a running engine has a certain time*area.
And finally dividing that TA value by the cylinder capacity, including the combustion volume (which everybody keeps forgetting) will give the specific time*area, which is an indication of how well an engine can breathe and at what rpm it will run out of breath.
By the way, I like to use the multiplication sign * in angle*area and time*area because I feel it clarifies what these expressions stand for.

While we are on the subject of breathing: STA is essential but it is not the only factor. You can have all the STA you want; with a pressure ratio ≤ 1 over a port no mass will start moving in the desired direction.

The third essential factor is inertia. Even with ample STA and a healthy pressure ratio a stationary gas column needs time to get up to speed. The longer and heavier the column, the slower it gets moving.
(when talking about intake ducts you might argue that such a sluggish column will give a useful ramming effect later on, but I would say that this is just an attempt at the end to make up for something that went wrong at the beginning).
Summary: it all comes down to ports and pipes. But you already knew that.
-------------------------------------------------------------------------------
Gordon Jennings certainly did a lot of good with his easy-to-read articles. But he created one misconception that is festering until this day, with his translation of the SAE-papers of Yamaha's Naitoh and Nomura into 'tuner's english'.
He extracted specific time*areas and claimed them to be the optimum values for a two-stroke. On the scavenging side he was as right as makes no difference, but on the exhaust side it was quite another story.
Naitoh and Nomura just stated their findings; Jennings concluded that specific exhaust time*area should be what Yamaha had been using. But Yamaha had by no means found a gasdynamic optimum; they just had gone as far as the quality of their piston rings allowed them to do. And had they thought of using auxiliary exhaust ducts (first seen in their present form in the 1971 Jamathi engine), they would have made a quantum leap.
Another point of criticism is that Jennings emphasized exhaust time*area and almost neglected blowdown time*area.
----------------------------------------------------------------

Thanks Frits

I was only just reading an article the other day and it mentioned the Jamathi winning the Italian Gp in about 69 so.
Jennings was easy to read and he did the reed opened by the pipe bit as well. Which most people seem to disagree with as well.But he did have an easy to follow style.
I do occasionally visit the other thread to see what has been added.

oh never picked up the "including the combustion volume" so thanks.

One last bit (I realise you are busy) is the crankcase volume most texts quote the peak speed at which the peak delivery ratio occurs as being inversely proportional to the square root of the crankcase volume (Ie higher revs need lower volume) yet seemingly the modern thinking doesn't follow this, is it about needing a certain reisivor volume available or just better duct flows and directional control nowdays?

oh yeah the virtual chocolate fish question answer was A BSA B25 Starfire I would also have accepted a Triumph 250 Tr25 Trophy. Or BSA 250 Goldstar SS.
Kickaha i am disappointed.

[dinamik2t]

Since the conversation came to old books, I would encourage anyone to give a look at Dixon's 2T book puplished in 2005.
I re-read random topics from time to time and have found lots of the stuff Frits or Wob (or even EngMod) "mention" here. It has lots of physics and formulas too, helping to better comprehend how each part functions.

It's rather cheap at an offer here, with free worldwide delivery : http://www.bookdepository.co.uk/High.../9781844250455

By the way, have you Frits or Wob read it, to share an opinion on it?

[Frits Overmars]

I would encourage anyone to give a look at Dixon's 2T book puplished in 2005......have you Frits or Wob read it, to share an opinion on it?

I haven't.

[Frits Overmars]

...is the crankcase volume most texts quote the peak speed at which the peak delivery ratio occurs as being inversely proportional to the square root of the crankcase volume (Ie higher revs need lower volume) yet seemingly the modern thinking doesn't follow this, is it about needing a certain reisivor volume available or just better duct flows and directional control nowdays?

Kinda hard to decipher that sentence. Are you sure you cannot write in Dutch, Husa? Anyways, square roots of volumes make me think of Helmholtz resonance. And if memory serves, I posted my 'Helmholtz blues' here not too long ago; you might want to take a look.
Nowadays an engine needs a large crankcase volume (the Aprilia RSA125's is 675 cc at TDC), all the port area you can cram into the cylinder circumference, good ducts for efficient flow and directional control, an exhaust that sucks and blows hard at the appropriate moments, and cooling, cooling, cooling.

[Kickaha]

Kinda hard to decipher that sentence. Are you sure you cannot write in Dutch, Husa? .

He can hardly write in English

[dinamik2t]

So, I had some free time and I tried to connect your discution on pressure waves with EngMod p.waveforms.
The above waves come from my test engine, at it's peak BMEP rpm.
In Honda RS, Yam TZ250 pre-loaded engines as well as the (~)RSA engine I have in EngMod, at the encircle point, TFR pressure is still above 1.

I added some letters to indicate points -me thought- of importance. Please correct me when I say something wrong in the following:

A: Ex port opens, flow starts there, pressure rises (why?). cylinder pressure starts dropping (still relatively too high). Tfr pressure irrelevant to Ex/Cyl pressure.
B: Ex pressure tops, flow speed tops. Cylinder pressure still dropping, gases exit. Tfr oscillate and starts rising, due to case/inlet pressure action.
C: Big depression in pipe, Ex pressure drops. Cylinder pressure drop dramaticaly, gases still exiting. Tfr open, pressure still rises.
D: Tfr pressure tops, start falling.
Blanks -lots of- follow.
E:
F:
G-K: Tfr pressure below 1. No flow?
K: Returning pulse from pipe arrives @ ex port, pressure starts rising. momentarily after, cylinder pressure starts rising. Tfr pressure rises a little more (flow?) before closing soon.
L: Ex pressure tops, a few degrees before closure. cylinder pressure rises, piston compressing hard. Tfr (closed) oscillation due to case/inlet action.
M: Ex pressure oscillation due to pipe action. cylinder pressure rises, piston truly compressing.
N:

Not much, but I have no head to combine every part's action into more analysis right know.

Hope I had a few right's above..
It would be very interesting to know what happens to TFR pressure and it falls at [C,F]. Also at [G,K] and their impact on flow.
(sorry, I ate a few letters after G - brains are pulverised as I said).

[husaberg]

He can hardly write in English

I can write dropped valves are great fun and ape hangers are only for Harley's. Can you? Warwick

Kinda hard to decipher that sentence. Are you sure you cannot write in Dutch, Husa? Anyways, square roots of volumes make me think of Helmholtz resonance. And if memory serves, I posted my 'Helmholtz blues' here not too long ago; you might want to take a look.
Nowadays an engine needs a large crankcase volume (the Aprilia RSA125's is 675 cc at TDC), all the port area you can cram into the cylinder circumference, good ducts for efficient flow and directional control, an exhaust that sucks and blows hard at the appropriate moments, and cooling, cooling, cooling.

The peak speed at which the peak delivery ratio occurs as being inversely proportional to the square root of the crankcase volume (Ie higher revs need lower volume)

It is nearly word for word from Robinson.
I think he was an Editor as well.

What it was saying was the last bit (Ie higher revs need lower volume)
Out of respect for you and some others i tend to post in Engerishish.

[wobbly]

I havnt read that book - so I just ordered it in case there is some small golden piece of info, you never know.

Re Blowdown STA numbers and the effect they have.
Firstly get out of your head completely the lawnmower engines view of the world that the piston dropping increases the pressure in the case, and it is this that forces the flow thru the transfers.
Mr Villiers creations may have operated this way - not any modern 2T.
When the transfers open, there is more pressure above the piston than there is case pressure in the transfer duct.
This gives rise to the alarming notion that when using staggered ports, the one to open first has so much backflow that it takes ages to recover, thus it has inflow last.
The area available in the Ex from the time the port cracks, down to where the transfers open, sets the amount of combustion pressure that is lost down the duct, and thus the amount of
positive pressure ratio across the open transfers ( and for how long this lasts ).
We can have NO FLOW until that positive pressure ratio is reduced to the point where we have more case pressure than cylinder pressure.
There are two ways to do this - lift the case pressure and or lower the cylinder pressure.
In a modern engine the case pressure is only rising very slowly due to the piston dropping, but what we do have is the pipe diffuser action, that started with the high pressure front ripping
out the opening Ex port - then entering the expanding pipes front section.
As the piston approaches BDC the Ex port is starting to suck the chrome off the proverbial towball,dropping the cylinder pressure ratio dramatically, and it is this that forces the bulk flow into the cylinder.
If the blowdown is set correctly for the power needed within the rpm band we want, then the recovery time from the unavoidable transfer backflow at the opening point, is such that we get the correct
amount of inflow to be trapped above the piston, thus creating the conditions for the correct amount of combustion pressure after the spark event.
It is this set of conditions - all revolving around the blowdown pressure,that ultimately creates how much combustion psi is developed - this creates torque, and it is this combined with rpm that creates POWER.